CN112352176A

CN112352176A - Triple clad optical fiber

Info

Publication number: CN112352176A
Application number: CN201980033555.7A
Authority: CN
Inventors: 伊恩·李
Original assignee: Nuburu Inc
Current assignee: Nuburu Inc
Priority date: 2018-05-04
Filing date: 2019-05-04
Publication date: 2021-02-09
Anticipated expiration: 2039-05-04
Also published as: WO2019213633A3; EP3788423A4; US20190361171A1; US20210405288A1; US11119271B2; WO2019213633A2; JP2021534437A; JP7311536B2; US12174414B2; CN117031615A; EP3788423A2; JP2023126936A; CN112352176B

Abstract

A multi-clad fiber optic assembly for reducing and eliminating deleterious laser-contaminant interactions, and methods of making such assemblies, are provided. An optical connector is provided having contaminants that are shielded from causing deleterious thermal effects during laser beam transmission by preventing laser-contaminant interactions. A multi-clad fiber optic assembly for reducing and eliminating deleterious laser-contaminant interactions, and methods of making such assemblies, are provided. An optical connector is provided having contaminants that are shielded from causing deleterious thermal effects during laser beam transmission by preventing laser-contaminant interactions.

Description

Triple clad optical fiber

This application claims benefit of filing date of U.S. provisional application No. 62/667,345 filed on 4.5.2018, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates to optical fibres, optical coupling to optical fibres and arrangements of optical fibres to enhance optical coupling to optical fibres.

Background

Additive manufacturing systems (additive manufacturing systems) based on Infrared (IR) (e.g. wavelengths greater than 700nm, especially wavelengths greater than 1000nm) suffer from, among other things, two disadvantages which limit the build volume and build speed.

As used herein, unless otherwise expressly specified, "UV," "ultraviolet light," "UV spectrum," and "UV portion of the spectrum" and similar terms are to be given their broadest meaning and include light having a wavelength of about 10nm to about 400nm and 10nm to 400 nm.

As used herein, unless otherwise expressly specified, the terms "high power," "multiple kilowatts," and "multiple kW" laser and laser beam and similar such terms refer to and include laser beams having a power of at least 1kW (non-low power, e.g., no less than 1kW), at least 2kW (e.g., no less than 2kW), at least 3kW (e.g., no less than 3kW), greater than 1kW, greater than 2kW, greater than 3kW, from about 1kW to about 5kW, from about 2kW to about 10kW, and other powers within these ranges and greater powers, and systems that provide or deliver laser beams.

As used herein, unless otherwise expressly specified, the terms "visible," "visible spectrum," and "visible portion of the spectrum," and similar terms, shall be given their broadest meaning and include light having a wavelength of about 380nm to about 750nm and about 400nm to 700 nm.

As used herein, unless otherwise specified, "optical connector," "fiber optic connector," "connector," and similar terms are to be given their broadest possible meaning and include any component into which a laser beam is or can be transmitted, any component into which a laser beam can be transmitted, and any component that transmits or receives or both transmits and receives a laser beam associated with, for example, free space (which includes vacuum, gas, liquid, foam, and other non-optical component materials), optical components, waveguides, optical fibers, and combinations of the foregoing.

As used herein, unless otherwise expressly stated, the term "proximal end" of a component (e.g., an optical fiber) refers to the end of the component that is closest to, e.g., receives a laser beam when the component is in optical communication with, a laser source. As used herein, unless otherwise expressly stated, the term "distal end" of a component (e.g., an optical fiber) refers to the end that is optically farthest from a laser source, e.g., the end from which a laser beam is emitted or transmitted, when the component is in optical communication with the laser source.

As used herein, unless otherwise expressly specified, the terms "blue laser beam," "blue laser," and "blue" shall be given their broadest meaning and generally refer to a system that provides a laser beam, a laser source, such as a laser and diode laser, that provides (e.g., transmits) a laser beam, or light having a wavelength of about 400nm to about 500 nm.

As used herein, unless otherwise expressly specified, the terms "green laser beam," "green laser," and "green" shall be given their broadest meaning and generally refer to a system that provides a laser beam, a laser source, such as a laser and diode laser, that provides (e.g., transmits) a laser beam, or light having a wavelength of about 500nm to about 575 nm.

Generally, unless otherwise specified, the term "about" as used herein is intended to encompass a variance or range of ± 10%, to encompass experimental or instrumental errors associated with obtaining the stated values, and preferably the larger thereof.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein. Unless otherwise indicated herein, each separate value within the range is incorporated into the specification as if it were individually recited herein.

The background of the invention section is intended to introduce various aspects of art, which are related to embodiments of the present invention. Accordingly, the preceding discussion in this section provides a framework for better understanding of the present invention and is not to be taken as an admission of prior art.

Disclosure of Invention

The present invention advances the art and addresses the long-standing need for efficient coupling of light, particularly high power laser beams, into optical fibers and transmission of light through such fibers. The present invention advances the art and addresses these problems and needs, among others, by providing articles, apparatus, and processes as taught and disclosed herein.

The use of a triple clad fiber to protect the laser from interaction with the housing or materials in the housing is provided.

Further, the use of a secondary cladding is also provided to protect the light from interaction with contaminants or other materials that could result in thermal, optical, or damage to the optical fiber. The function of the material to outgas from contaminants due to light interaction at the cladding interface.

In addition, a triple clad fiber design with optional end caps is provided.

Still further, these methods, optical fibers and assemblies are provided having one or more of the following features: wherein the cladding defines an outer surface; and wherein the outer surface has contaminants.

There is also provided an optical fiber connector assembly having: a triple-clad optical fiber having a proximal end and a distal end, a length defined therebetween; the optical fiber has a core, an inner cladding in direct contact with the core, a second cladding adjacent the inner cladding, and an outer cladding adjacent the second cladding; wherein the outer cladding has been removed along a proximal portion of the length of the optical fiber, thereby defining a proximal length of the optical fiber and exposing an outer surface of the second cladding along the proximal length, the outer surface having contaminants; and, the proximal length is located in the lumen of the connector, whereby contaminants are located between the inner surface of the connector and the outer surface of the second cladding; thereby, the contaminant is shielded by the second cladding layer, leaving the contaminant unaffected by the laser energy in the inner cladding layer; thereby minimizing detrimental thermal effects from laser-contaminant interactions.

Additionally, these methods, optical fibers, and assemblies are provided having one or more of the following features: wherein the connector has an end cap to which the proximal end of the optical fiber is optically connected; wherein the distal end of the optical fiber is optically connected to the single clad optical fiber; wherein the optical connection is a splice; wherein the single clad fiber has a modal canceller; wherein the contaminant covers more than about 5% of the surface of the proximal length of the optical fiber; and wherein the contaminant covers more than about 10% of the outer fiber surface in contact with the inner surface of the connector.

Further, there is provided an optical fiber connector assembly having: an optical fiber having a proximal end and a distal end defining a length therebetween; the optical fiber has a core, an inner cladding in direct contact with the core, a second cladding adjacent the inner cladding; the second cladding having a region along the length of the optical fiber wherein the outer surface of the optical fiber is contaminated with contaminants that cause thermal degradation of the optical fiber upon interaction with the laser beam; thereby defining an outer contaminated area; and, the outer contaminated area is in direct contact with the inner surface of the connector; thus, the contaminant is shielded by the second cladding layer, so that the contaminant is not affected by the laser energy in the inner cladding layer; thereby preventing thermal degradation of the optical fiber.

In addition, methods of transmitting laser beams through these components are provided; wherein the laser beam has one or more of the following characteristics: a power of about 1W to about 10 kW; a power of about 1W to 50 kW; a power of about 5W to 2 kW; a blue wavelength; a blue-green wavelength; a green wavelength; and wherein the assembly does not thermally degrade.

Further, there is provided a method of manufacturing a contaminated optical connector that does not thermally degrade when transmitting a laser beam, the method comprising: obtaining a triple-clad optical fiber; the optical fiber has a core, an inner cladding adjacent to the core, a second cladding adjacent to the inner cladding, and an outer cladding adjacent to the second cladding; removing a portion of the outer cladding layer, thereby exposing a surface of the second cladding layer; the surface of the second cladding has a contaminant, thereby defining a contaminated outer surface; and inserting the proximal end of the optical fiber into the connector; wherein at least a portion of the contaminated surface is in direct contact with the inner surface of the connector; thus, the contaminant is shielded by the second cladding layer, so that the contaminant is not affected by the laser energy in the inner cladding layer; thereby preventing the deleterious thermal effects of laser-contaminant interactions.

Still further, there is provided transmitting a laser beam having a power of about 10W to about 20kW through a contaminated optical connector assembly having a triple-clad optical fiber without causing detrimental thermal effects to the optical fiber or connector due to contamination in the assembly.

Further, methods, optical fibers, and assemblies are provided having one or more of the following features: the method of claim 11, wherein the contaminant is located between an outer surface of the optical fiber and an inner surface of the body of the connector.

Further, these methods, optical fibers, and assemblies are provided having one or more of the following features: wherein laser energy is delivered for a total duration of at least 1000 hours without causing detrimental thermal effects; wherein laser energy is delivered for a total duration of at least 100 hours without causing detrimental thermal effects; wherein laser energy is delivered for a total duration of at least 500 hours without causing detrimental thermal effects; wherein laser energy is delivered for a total duration of at least 1000 hours without causing detrimental thermal effects; wherein the laser beam is delivered for 1 to 500 duty cycles of the laser system without causing detrimental thermal effects; wherein the laser beam is delivered for 1 to 2000 duty cycles of the laser system without causing detrimental thermal effects; wherein the laser beam is delivered for more than 500 duty cycles of the laser system without causing detrimental effects; wherein the laser beam is delivered for over 1000 duty cycles of the laser system without causing detrimental thermal effects; and wherein the laser beam is delivered for more than 5000 duty cycles of the laser system without causing detrimental thermal effects.

Still further, a method of assembling an assembly for a laser system, the assembly configured for a laser beam having a power of about 50W to about 50kW, the method having the steps of: providing an optical fiber having a core, a first cladding surrounding the core, a second cladding surrounding the first cladding, and an outer layer surrounding the second cladding; removing the outer layer, thereby exposing an outer surface of the second cladding; whereby the contaminant is associated with the outer surface; inserting an optical fiber into a structure having a cavity, the cavity defining an inner surface; leaving at least about 100% of the contaminants associated with the outer surface; inserting the optical fiber into the cavity, whereby the contaminant is located between the outer surface and the inner surface; wherein the optical fiber is capable of receiving and transmitting a laser beam having a power of about 50W to about 50kW without being damaged by interaction between the laser beam and contaminants.

Still further, such methods, optical fibers, and assemblies are provided having one or more of the following features: wherein the outer surface cannot be cleaned; wherein the outer surface is not polished; wherein the inner surface has contaminants associated therewith; wherein the inner surface is not cleaned; where 90% of the contaminants are left; in which 80% of the contaminants are left behind; in which 50% of the contaminants are left behind; wherein 20% of the contaminants are left behind; wherein the contaminant is on the outer surface; wherein the contaminant is embedded in the outer surface; wherein after insertion, the contaminant is embedded in the inner and outer surfaces; wherein the structure is a ferrule; wherein the inner surface and the outer surface are in direct contact; wherein the laser power is about 50W to 1 kW; wherein the laser power is about 1W to 10W; wherein the power is from about 100W to about 500W; wherein the power is from about 100W to about 200W; wherein the power is about 150W; and wherein the power is from about 1kW to about 20W.

Drawings

FIG. 1 is a perspective view of a prior art optical fiber illustrating the problems with these fibers.

Fig. 2 is a perspective view of an embodiment of an optical fiber according to the present invention.

Fig. 3 is a cross-sectional view of an embodiment of an optical fiber connector according to the present invention.

Fig. 4 is a cross-sectional view of an embodiment of a fiber optic splice according to the present invention.

Fig. 5 is a cross-sectional view of an embodiment of a cladding light mode stripper (cladding light mode stripper) according to the present invention.

Detailed Description

The present invention relates generally to the deployment of optical fibers, and more particularly to the deployment of optical fibers for the transmission of high power laser beams. Embodiments of the present invention relate to arrangements of optical fibers, optical connectors, optical couplers and optical fiber splices for mitigating and eliminating the detrimental effects of contaminants located outside the fiber core.

Thus, in general, an optical fiber may have a core, a cladding, and may have additional cladding, as well as coatings and other protective layers. For example, the optical fiber may be a hollow core photonic crystal or a solid core photonic crystal. Typically, the fiber cladding surrounds the core, and the coating (if present) surrounds the cladding, while the other protective layers (if present) surround the coating. The core typically has a circular cross-section, although other shapes, such as square, are also contemplated. In an embodiment, the optical fiber or a length of the optical fiber is free of cladding.

The optical fiber may be single mode or multimode. If multi-mode, the Numerical Aperture (NA) of the embodiments may be in the range of 0.1 to 0.6.

The core may be composed of fused silica. The core may have a cross-section, such as a diameter, including all diameters within this range, as well as larger and smaller diameters, from about 5 micrometers (μm) to about 1500 μm, from about 10 μm to about 1000 μm, from about 8 μm to about 65 μm.

The cladding may be comprised of fluorine-doped fused silica or other materials, such as fused silica doped with index-altering ions (e.g., germanium). The cladding thickness depends to some extent on the diameter of the core, however, the cladding thickness can be from about 10 μm to about 300 μm, about 40 μm to about 250 μm, and about 20 μm to about 150 μm, including all thicknesses within this range and greater and lesser thicknesses. As used herein with respect to multilayer structures, the term "thickness" refers to the distance between the inner diameter (or inner surface) of a layer and its outer diameter (or outer surface). The thickness of the cladding depends on the single mode or multimode configuration and may be related to the core size and the desired wavelength. Generally, the outer diameter of the cladding should be 1.1 to 1.2 or more times the outer diameter of the core.

Generally, in the step index fiber embodiment, the index of refraction of the core is constant and the index of refraction of the cladding is lower than the index of refraction of the core. In a multi-clad fiber, the refractive index of the cladding may vary. In an embodiment, the optical fiber may be a graded index fiber, wherein typically the refractive index of the core decreases with increasing distance from the optical axis (e.g., center) of the optical fiber.

The coating may be, for example, an acrylate polymer, polyimide, or other material.

Generally, when light (e.g., a laser beam) and blue, blue-green, and green laser beams are coupled (e.g., emitted) into an optical fiber (e.g., a typical step-index fiber), some of the light enters the cladding as well as the core. As light is emitted into the cladding, the light interacts with contaminants present in the cladding, on the surface of the cladding, or both. Contaminants may also be present on the inner surface of the component that is in direct contact with the outer surface of the optical fiber, such as when the optical fiber is inserted into a ferrule.

For example, during assembly of various lasers and optical systems, the outer non-glass cladding materials, such as coatings and protective layers, of the optical fiber are stripped. This is done for a variety of reasons, including preventing damage to these outer non-glass layers due to interaction with the laser. Such interaction can lead to scattering, which leads to further interaction, heating and thermal reactions, and other deleterious phenomena, thereby damaging the optical fiber, components of the system, and both.

However, when these layers are removed, contaminants are typically left behind. These contaminants may be, for example, dust, epoxy, or polishing compounds that become trapped on or in the optical fiber or that are present between the outer surface of the optical fiber and the inner surface of the component (e.g., ferrule) in which the optical fiber is located. Thus, for example, such contaminants may be located between the connector ferrule and the optical fiber.

It is believed that physical removal of these contaminants, and in a manner that does not compromise the physical and optical properties of the fiber, is very difficult and expensive, and sometimes impractical.

In some systems, a large amount of power is transmitted in the fiber cladding due to the emission conditions at the proximal end of the fiber or back reflection at the distal end of the fiber. This can lead to thermal damage to the fiber or outgassing from the ferrule material, resulting in fiber degradation. The outgassed material may also deposit on the surface of the fiber, resulting in loss of fiber function.

Due to the construction process, the material trapped around the fiber cannot be easily relaxed.

Thus, turning to FIG. 1, there is a perspective schematic view of an embodiment of a prior art optical fiber illustrating the problem of cladding laser energy interacting with contaminants associated with the cladding. The optical fiber 100 has a core 101 surrounded by a cladding 102. The cladding has an outer surface 103 with

contaminants

104a, 104b on, in, or otherwise mechanically, chemically, or both associated with the outer surface 103, the cladding 102, or both, or

contaminants

104a, 104b on, in, or both the outer surface 103, the cladding 102, and

contaminants

104a, 104b otherwise mechanically, chemically, or both associated with the outer surface 103, the cladding 102, or both. The cladding light energy shown by arrow 106 can escape the cladding as shown by

arrows

106a, 106b, 106c, and 106 d. This light escaping from the cladding interacts with the

contaminants

104a, 104b causing unwanted thermal interactions 108, which thermal interactions 108 can degrade and damage the optical fiber.

Embodiments of the present invention address this problem by reducing, and preferably eliminating, the interaction of cladding laser energy with such contaminants. In this way, such detrimental interactions are avoided without the need to remove contaminants.

Turning to FIG. 2, a perspective schematic view of an embodiment of a fiber configuration that addresses, mitigates, and preferably eliminates these detrimental laser-contaminant interactions is shown. A solution to this problem may be achieved by using an embodiment of the triple-clad fiber 200. The triple cladding comprises a non-glass material such as an acrylate. This non-glass layer is removed from a small area of the optical fiber (and thus not shown in the figures) during the fiber optic connector assembly process. The optical fiber 200 has a core 201, a first cladding 202, and a second cladding 203, the second cladding 203 having an outer surface 204. The fiber has

contaminants

205a, 205 b.

Contaminants

205a, 205b may be in, on, or otherwise mechanically, chemically, or both in relation to surface 205, cladding 203, or

contaminants

205a, 205b may be in, on, or otherwise mechanically, chemically, or both in relation to surface 205, cladding 203. It should be appreciated that typically the contaminants are on the surface 205. By dimensioning the first cladding and the second cladding, for example a first cladding with an outer diameter of 230 μm to 250 μm and a second cladding with a diameter of 280 μm, light that is correctly emitted in the fiber or focused back into the fiber by back reflection can be contained mainly by the first cladding, while a very small part of the light is in the second cladding. Cladding light energy 207, which may be of higher power, may be launched into first cladding 202, and very weak cladding light energy 208 may also be launched into second cladding 203. The second cladding 203 shields any contaminants, e.g., 205a, 205b, from interaction with the higher power cladding optical energy 207. The cladding 203 also shields contaminants from the light energy emitted into the core 201, which may leak into the first cladding 202. The reduction in power transmission in the second cladding minimizes, and preferably eliminates, the possibility of material outgassing or thermal damage to the fiber at the expected (e.g., specified) fiber usage power level. The fiber configuration of this embodiment reduces, minimizes and preferably eliminates detrimental thermal effects that would otherwise be caused by contaminants associated with the outer surface of the fiber. In this manner, as further illustrated by the other embodiments and teachings of the present specification, embodiments of optical fibers of the present invention can be safely, successfully, and effectively used in connectors, couplers, and other optical devices or interfaces despite having contaminants on the surface of the optical fiber, for example, on the surface of the optical fiber that contacts or is adjacent to the surface of the optical device associated with the optical fiber. Thus, nevertheless, avoiding complex and expensive cleaning steps may not successfully eliminate these contaminants. Further, it should be understood that in some cases (e.g., critical-use applications), such a cleaning step may be used as a production step to improve the quality of the optical fiber of the present invention, but is not required.

Embodiments of the present invention employ such a triple-clad fiber configuration as part of a component or configuration in various laser and optical systems in which the fiber is connected to other components, laser beams are transmitted or received, back reflections are received, and fiber-to-fiber connections are made, to name a few.

Turning to fig. 3, a cross-sectional schematic view of an embodiment of a fiber optic connector structure 300 is shown, the fiber optic connector structure 300 addressing, mitigating, and preferably eliminating these detrimental laser-contaminant interactions. The optical fiber 309 comprises an optical core 310 with a diameter of 200 μm and a nominal NA of 0.22, surrounded by a first cladding 311 with an outer diameter of 250 μm and an NA of 0.24. The first cladding layer 311 allows the emitted high power laser beam to propagate in the optical core 310. The second cladding 312 had an outer diameter of 280 μm and an NA of 0.26. The second cladding 312 contains the light in the first cladding so that the light is transmitted in the first cladding and any light transmission in the second cladding 312 is minimized. The fiber length is long enough to protect the fiber connector 302 and ferrule 307 structure with any associated

contaminants

303a, 303b before it is spliced to a conventional single clad fiber and then can interact with a fiber optic mode stripper.

The outer non-glass layer 370 of the triple-clad fiber 309 is shown. It can be seen that for the portion of the optical fiber 309 within the connector body 302, the layer 370 has been stripped from the optical fiber 309.

The fiber optic connector structure 300 has a connector body 302, the connector body 302 housing an end cap 301, a ferrule 307, and an optical fiber 309. The optical fiber 309 is in optical communication with the end cap 301. Preferably, the optical fiber 309 is mechanically and optically connected to the end cap 301.

Contaminants are shown in the figure as darker lines and dashed lines, e.g. 303a, 303 b. The contaminants are located between the outer surface 330 of the second cladding 312 of the fiber and the inner surface 340 of the ferrule 207.

Turning to FIG. 4, a cross-sectional schematic view of an embodiment of a fiber optic joint structure 400 is shown, where the fiber optic joint structure 400 addresses, mitigates, and preferably eliminates harmful laser-contaminant interactions. In this embodiment, there is a fiber connector structure 400 a. The optical fiber 409 comprises an optical core 410 with a diameter of 200 μm and a nominal NA of 0.22, the optical core 410 being surrounded by a first cladding 411 with an outer diameter of 250 μm and an NA of 0.24. The first cladding 411 allows the emitted high power laser beam to propagate in the optical core 410. The second cladding 412 had an outer diameter of 280 μm and an NA of 0.26. The second cladding layer 412 contains the light in the first cladding layer such that the light is transmitted in the first cladding layer and minimizes the transmission of any light in the second cladding layer 412. (other optical core diameters and cladding thicknesses, such as those described in this specification, may be used.)

The fiber optic connector structure 400a has a connector body 402, the connector body 402 housing an end cap 401, a ferrule 407, and an optical fiber 409. The optical fiber 409 is in optical communication with the end cap 401. Preferably, the optical fiber 409 is mechanically and optically connected to the end cap 401.

Contaminants are indicated in the figure by darker lines and dashed lines, e.g. 403a, 403 b. The contaminants are located between the outer surface 430 of the fiber 409 and the inner surface 440 of the ferrule 407.

The length of the optical fiber 409 is long enough to protect the fiber connector 402 and ferrule 407 structure with the associated contaminants 403a, 403b, after which the splice 430 is spliced to a conventional single-clad fiber 450 (having a core 410a and a cladding 451).

The direction of travel of light energy in the cladding 411 is away from the end cap 401, toward and through the joint 430 and into the cladding 451, as indicated by arrow 420. Thus, in this embodiment, the cladding light is launched into the cladding of the second optical fiber through the splicing hair. It will be appreciated that the core may have a larger diameter and thus cause cladding light from the inner cladding of a double-clad optical fibre to be incident into the core of a single-clad optical fibre.

All combinations of fibers having two, three or more ("n" s) cladding, optically connected to fibers spliced, for example, to fibers having n-1 or n-2 claddings, are contemplated, with laser light preferably being transmitted from fibers having more cladding to fibers having less cladding. Embodiments may also have two optical fibers optically connected, the two optical fibers having the same number of cladding layers.

Turning to fig. 5, fig. 5 is a cross-sectional schematic view of an embodiment of a modal eliminator and joint configuration that addresses, mitigates, and preferably eliminates detrimental laser-contaminant interactions. In this embodiment, fiber joint structure 400 (from the embodiment of fig. 4, all structures are the same, with leads omitted for simplicity, like numerals indicating the same structures) has its single-clad fiber 450, with mode stripper region 500 in the single-clad fiber 450. Region 500 has a mode stripper 510 that removes cladding light from the cladding, passes the cladding light to heat sink element 502, where the energy is converted to heat and dissipated or otherwise removed in heat sink element 502.

In the embodiment of the schematic shown in fig. 5, the light transmitted from the inner cladding 412 is removed by a mode stripper 500 located near the junction 450. In addition to the mode stripper 500, the fiber 450 may be buffered with an acrylate or silicone cladding and a buffer material.

Embodiments of the present invention reduce and preferably eliminate the need to remove contaminants associated with the outer surface of the optical fiber (e.g., the outer surface of the cladding, the inner surface of the cavity that receives the outer surface in the assembly, and both). In this manner, the need for expensive, time consuming and potentially damaging cleaning and polishing steps in the manufacture of the assembly is minimized, reduced and preferably eliminated.

In embodiments, 100%, about 5% to about 99%, about 10%, about 20%, about 25% to about 90%, about 50% or more, about 70% or more, about 60% to 100%, and all percentages within these ranges of contaminants can be associated with the surface during assembly manufacturing and remain in the final assembly without causing laser-contaminant interactions during laser beam delivery. Thus, for example, 1% to 100% of the outer surface of the optical fiber in direct contact with the inner surface of the interface device (e.g., the inner surface of the ferrule or the inner surface of the connector) may have contaminants thereon. In addition, about 1% to about 25%, about 5% to about 70%, about 15% to about 30%, and about 20% to about 80% of the outer fiber surface may have contaminants thereon, thereby causing laser-contaminant interactions during laser beam delivery.

The present embodiments may be applied to high power laser systems such as welding, cutting, additive manufacturing, additive-subtractive manufacturing, and other laser processing systems, including industrial, manufacturing, telecommunications, and medical systems. They are suitable for use with laser energy of all wavelengths, including laser energy of light, including laser beams of UV, visible and infrared wavelengths. They are suitable for laser systems of various power laser beams, such as 0.01kW to 0.1kW, 0.1kW to 0.5kW, about 1kW, about 5kW, about 10kW, about 20kW, about 50kW, about 1kW to about 20kW, about 5kW to about 50kW, about 10kW to about 40kW, and all powers within these ranges as well as high and low powers.

In examples of these embodiments of multi-clad fibers, the fiber stub and the cladding optical mode stripper are configured to operate in a system utilizing laser energy in the range of 100W to 200W, preferably 150W. The system may be, for example, a laser welding system or a 3D printer, a laser welder, a laser cutter, and similar types of laser manufacturing systems.

In an embodiment, preferred wavelengths for a system using the optical fiber, connector and connector structure of the present invention are blue and green wavelengths, including wavelengths of 450nm, 515 nm. In embodiments, the blue and green wavelength beams have beam masses of 21mm mrad to 12mm mrad, 10mm mrad to 70mm mrad, 15mm mrad to less than 1mm mrad, less than about 15mm mrad, less than about 10mm mrad, less than about 5mm mrad, and about 1mm mrad, as well as all values within these ranges and greater and lesser values.

It should be noted that no theory need be presented or presented that emphasizes new and inventive processes, materials, properties, or other advantageous features and properties that are the subject of or associated with embodiments of the present invention. However, various theories are provided in this specification to further advance the art in this field. The theory presented in this specification in no way limits, limits or narrows the scope of the claimed invention unless explicitly stated otherwise. Many of these theories are not required or practical to utilize the present invention. It should also be appreciated that the present invention may lead to new, heretofore unknown theories as to explain the functional characteristics of embodiments of the methods, articles, materials, devices, and systems of the present invention; so that the theory developed hereafter should not limit the scope of the present invention.

The various embodiments of systems, devices, techniques, methods, activities, and operations set forth in this specification can be used in various other activities and in other fields than those set forth herein. Additionally, for example, these embodiments may be used with: other devices or activities that may be developed in the future; and, based on the teachings of this specification, existing equipment or activities may be partially modified. Further, the various embodiments set forth in this specification can be used in various different combinations with one another. Thus, for example, the configurations provided in the various embodiments of the present description may be used with one another; moreover, the scope of the present invention should not be limited to the configurations or arrangements set forth in the particular embodiments, examples, or embodiments in the particular drawings.

The present invention may be embodied in other forms than those specifically disclosed herein without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.

Claims

1. An optical fiber connector assembly, comprising:

a. a triple-clad optical fiber having a proximal end and a distal end, with a length defined between the proximal end and the distal end; the optical fiber includes a core, an inner cladding in direct contact with the core, adjacent to the a second cladding of the inner cladding and an outer cladding adjacent to the second cladding;

b. wherein along the proximal portion of the length of the fiber, the outer cladding has been removed, thereby defining the proximal length of the fiber and exposing the second cladding along the proximal length the outer surface of the outer surface that contains contaminants; and,

c. the proximal length is located in the lumen of the connector, whereby the contamination is located between the inner surface of the connector and the outer surface of the second cladding;

d. The contaminants are thus shielded by the second cladding from the laser energy in the inner cladding; thereby minimizing detrimental thermal effects from laser-contaminant interactions.

2. The fiber optic connector assembly of claim 1, wherein the connector includes an end cap and the proximal end of the optical fiber is optically connected to the end cap.

3. The assembly of claim 2, wherein the proximal end of the optical fiber is optically connected to a single-clad optical fiber.

4. The assembly of claim 3, wherein the optical connection is a joint.

5. The assembly of claim 2, wherein the single-clad fiber includes a mode canceller.

6. The assembly of claim 1, 2, 3, 4, or 5, wherein the contamination covers more than about 5% of the surface of the proximal end length of the optical fiber.

7. The assembly of claim 1, wherein the contamination covers more than about 10% of the outer fiber surface in contact with the inner surface of the connector.

8. An optical fiber connector assembly, comprising:

a. an optical fiber having a proximal end and a distal end, defining a length between the proximal end and the distal end; the optical fiber includes a core, an inner cladding in direct contact with the core, adjacent the inner cladding the second cladding;

b. The second cladding comprises a region along the length of the optical fiber wherein the outer surface of the optical fiber is contaminated with contaminants that cause thermal degradation of the optical fiber upon interaction with the laser beam ; thereby defining the outer contaminated area; and,

c. the outer contamination area is in direct contact with the inner surface of the connector; thus, the contamination is shielded by the second cladding, so that the contamination is not affected by the laser energy in the inner cladding; Thereby thermal degradation of the optical fiber is prevented.

9. A method of delivering a laser beam through the assembly of claim 1 or 9; wherein the laser beam has a power of about 1 W to about 10 kW and a wavelength in the blue, cyan or green wavelength range, and wherein the components are not subject to thermal degradation.

10. A method of making a contaminated optical connector that does not thermally degrade when transmitting a laser beam, the method comprising:

a. obtaining a triple-clad optical fiber; the optical fiber includes a core, an inner cladding adjacent to the core, a second cladding adjacent to the inner cladding, and an outer cladding adjacent to the second cladding;

b. removing a portion of the outer cladding, thereby exposing the surface of the second cladding; the surface of the second cladding comprising contaminants, thereby defining a contaminated outer surface; and,

c. inserting the proximal end of the optical fiber into a connector; wherein at least a portion of the contaminated surface is in direct contact with the inner surface of the connector;

d. Thus, the contaminants are shielded by the second cladding from the laser energy in the inner cladding; thereby preventing detrimental thermal effects from laser-contaminant interactions.

11. Transmission of a laser beam at a power of about 10 W to about 20 kW through a contaminated optical connector assembly comprising a triple-clad optical fiber without detrimental thermal effects on the fiber or the connector due to contamination in the assembly.

12. The method of claim 11, wherein the contamination is located between an outer surface of the optical fiber and an inner surface of the body of the connector.

13. The method of claim 11 or 12, wherein the laser energy is delivered for a total duration of at least 1000 hours without causing detrimental thermal effects.

14. The method of claim 11, wherein the laser energy is delivered for a total duration of at least 100 hours without causing detrimental thermal effects.

15. The method of claim 11, wherein the laser energy is delivered for a total duration of at least 500 hours without causing detrimental thermal effects.

16. The method of claim 11, wherein the laser energy is delivered for a total duration of at least 1000 hours without causing detrimental thermal effects.

17. A method of assembling a component for a laser system, the component being configured for a laser beam having a power of about 50 W to about 50 kW, the method comprising:

a. providing an optical fiber having a core, a first cladding surrounding the core, a second cladding surrounding the first cladding, and an outer layer surrounding the second cladding;

b. removing the outer layer, thereby exposing the outer surface of the second cladding; whereby contaminants are associated with the outer surface;

c. inserting the optical fiber into a structure having a cavity defining an inner surface;

d. leaving at least about 100% of said contaminants associated with said outer surface;

e. inserting the optical fiber into the cavity, whereby the contamination is located between the outer surface and the inner surface;

f. wherein the optical fiber is capable of receiving and transmitting a laser beam having a power of about 50 W to about 50 kW without being damaged by the interaction between the laser beam and the contaminant.

18. The method of claim 17, wherein the outer surface cannot be cleaned.

19. The method of claim 17, wherein the outer surface is not polished.

20. The method of claim 17, wherein the inner surface has contaminants associated therewith.

21. The method of claim 17, wherein the inner surface is not cleaned.

22. The method of claim 17, wherein 90% of the contaminants remain.

23. The method of claim 17, wherein 80% of the contaminants remain.

24. The method of claim 17, wherein 50% of the contaminants remain.

25. The method of claim 17, wherein 20% of the contaminants remain.

26. The method of claim 17, wherein the contaminant is on the outer surface.

27. The method of claim 17, wherein the contaminants are embedded in the outer surface.

28. The method of claim 17, wherein after insertion, the contaminants are embedded in the inner surface and the outer surface.

29. The method of claim 17, wherein the structure is a ferrule.

30. The method of claim 17, wherein the inner surface and the outer surface are in direct contact.

31. The method of claim 17, wherein the power is about 50W to 1 kW.

32. The method of claim 17, wherein the power is about 100W to about 500W.

33. The method of claim 17, wherein the power is from about 100W to about 200W.

34. The method of claim 17, wherein the power is about 150W.

35. The method of claim 17, wherein the power is from about 1 kW to about 20 kW.